백준 C++ 10845번) 큐

https://www.acmicpc.net/problem/10845

10845번: 큐

 

queue STL를 사용하여 풀었습니다.

 

#include<iostream>
#include<queue>

using namespace std;

int main() {
	ios::sync_with_stdio(0);
	cin.tie(nullptr);
	int n;
	queue<int> q;

	cin >> n;
	for(int i = 0;i<n;i++) {
		string s;
		
		cin >> s;
		if (s == "push") {
			int input;
			cin >> input;
			q.push(input);
		}
		else if (s == "front") {
			if (q.empty())
				cout << -1 << "\n";
			else
				cout << q.front() << "\n";
		}
		else if (s == "back") {
			if (q.empty())
				cout << -1 << "\n";
			else
				cout << q.back() << "\n";
		}
		else if (s == "size") {
			cout << q.size() << "\n";
		}
		else if (s == "empty") {
			if(q.empty())
				cout << 1 << "\n";
			else
				cout << 0 << "\n";
		}
		else if (s == "pop") {
			if (!q.empty()) {
				cout << q.front() << "\n";
				q.pop();
			}
			else {
				cout << -1 << "\n";
			}
		}
	}
}